Behavioral avoidance predicts treatment outcome with exposure and response prevention for obsessive-compulsive disorder

Background: Many individuals with obsessive-compulsive disorder (OCD) display behavioral avoidance related to their obsessional thoughts and compulsive behaviors. However, how these avoidance behaviors impact treatment outcomes with exposure and response prevention (EX/RP) remains unclear. We examined pretreatment avoidance behaviors as predictors of EX/RP outcomes. Methods: Data came from a randomized controlled trial of augmentation strategies for inadequate response to serotonin reuptake inhibitors comparing EX/RP (N = 40), risperidone (N = 40), and placebo (N = 20). Baseline avoidance was rated with the avoidance item from the Yale-Brown Obsessive-Compulsive Scale (YBOCS). Primary analyses examined avoidance behaviors as predictors of EX/RP outcomes. To test specificity, we explored whether avoidance also related to outcomes among patients receiving risperidone and placebo. Results: More than half (69%) of the full sample had moderate or severe avoidance behaviors at baseline. In EX/RP, controlling for baseline severity, pretreatment avoidance predicted post-treatment YBOCS symptoms (beta = 0.45, P < .01). Avoidant individuals were less likely to achieve remission with EX/RP (odds ratio = 0.04, 95% confidence interval [CI] range 0.01-0.28, P = .001). Baseline avoidance was also associated with degree of patient adherence to between-session EX/RP assignments, which mediated the relationship between baseline avoidance and EX/RP outcomes (P<.05). Baseline avoidance did not predict outcomes or wellness among patients receiving risperidone or placebo. Conclusions: These results suggest that avoidance behaviors are an important clinical factor in EX/RP outcomes and indicate that assessing avoidance may provide an efficient method for predicting EX/RP outcomes. Avoidance may be particularly relevant in EX/RP as compared to medication treatment, though future replication of these initial results is required.